Researcher sees huge growth in podcast audience

The number of people who download free audio programs known as podcasts is set to explode over the next few years, according to a new report.

Researchers at the Diffusion Group predicted this week that the U.S. podcast audience will climb from 840,000 last year to 56 million by 2010. By that time, three-quarters of all people who own portable digital music players will listen to podcasts, up from less than 15 percent last year, the digital entertainment research group said.

The forecast comes amid much hype over podcasting. Apple Computer, whose iPod music player spawned the term "podcast," recently added 3,000 podcast programs to its iTunes online music store. And what started out as a system for distributing homespun radio programming over the Web has now caught on with big media companies. ABC News, NBC News, ESPN Disney and National Public Radio have all introduced podcast programming in recent months.

Apple's move to promote podcasts will bolster the trend, noted Marc Freedman, who wrote the Diffusion Group's report. "It will absolutely continue to fuel this explosive growth in podcasting," he said.

In addition to his work for the Diffusion Group, Freedman is the chief executive officer of file-sharing software start-up RazorPop, which facilitates the swapping of media files, including podcasts, over the Web.

But collecting podcast statistics is a tricky business. The Pew Internet and American Life Project created a stir a few months ago when it claimed a whopping 6 million Americans are listening to podcasts. The nonprofit's research director later backtracked when pressed by blog Engadget, admitting the number was probably too high because of the way the group phrased its survey.

Even the Diffusion Group's figures are much higher than those found in podcast forecasts from other research firms. For instance, Forrester Research predicted in April that just 12.3 million U.S. households will use MP3 players to listen to audio podcasts by the end of the decade.

Freedman said he based his forecast on the Diffusion Group's data on sales of portable digital music players and high-speed Internet penetration. The report was not based on a survey, he said. The Diffusion Group, a research firm formed last year in Dallas, employs 10 analysts and advises a number of major electronics companies, including Microsoft, Intel, Hewlett-Packard and Dell.